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Have a magnavox 31mf231d power board issue, replaced all caps. Had 1 obvious bad (2074). when powering up I get good power light, backlights come on, but only get gray screen. no menu, no controls. Also have a toshiba doing the same thing. I suspect that the tconn is not getting power. Is there a switch that may have been overloaded from bad cap. Looks like 7073 may be a transistor of some sort and appears to be in this circuit. Any suggestions?

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  • 11 more comments 
  • wayne_ostran Nov 10, 2010

    is there anything to replace on the main board? or is it pretty much a swap out and hope for the best?

  • wayne_ostran Nov 10, 2010

    its a 37mf231d, sorry for the confusion. I'll take any manual that will help. guessing gets expensive. Let me know how you can send the manual, and if I need to give you an email address

  • wayne_ostran Nov 10, 2010

    37mf321d

  • wayne_ostran Nov 10, 2010

    http://www.fixya.com/support/t2696949-ma...

    This seems to be my same situation but it looks like he is recomending a replacement of an inductor with a diode? could this be right?

  • wayne_ostran Nov 10, 2010

    I replaced 5 caps, 2074, 2082, 2081, 2080,

  • wayne_ostran Nov 10, 2010

    Thank you for your great help

  • wayne_ostran Nov 11, 2010

    Working through the troubleshoooting and do not have voltage on pin 6

  • wayne_ostran Nov 11, 2010

    No voltage out of 1088 pin 6

  • wayne_ostran Nov 11, 2010

    not tested, I have it scattered across the living room floor. Cant bring up menu, channels, or volume bar

  • wayne_ostran Nov 11, 2010

    After two days Im at my end. Im open to suggestions. the power board sounds logical to me. is that what you would do

  • wayne_ostran Nov 11, 2010

    what controls the power to 6

  • wayne_ostran Nov 11, 2010

    yes backlight is lit, but cannot bring up the menu. power light is solid (not blinking) Page 90 chart show pin 6 with 2.6v and pin 7 with 6.7v. I've connected video feed to all inputs with no change

  • wayne_ostran Nov 11, 2010

    thanks will do and let you know how it turns out

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  • 4,889 Answers

No its not the t-con. The t-con is only responsible for displaying an image. It will not affect the sound. Since you have no sound either you should shift your diagnosis to main audio/video board. You do not have to turn on any switch manually. The relays will turn themselves on if everything is perfect.

Posted on Nov 10, 2010

  • 10 more comments 
  • eagle338
    eagle338 Nov 10, 2010

    It depends. There is a micro-processor IC on it that is irreplaceable. As for your model number I do not remember seesing a 31MF231D. If its a 32MF231D, I have a comprehensive service manual that I can give you. It should make your job a lot easier. Ofcourse I will guide you if you need something. So the first thing you should check is the model number. A google search for your model returns hardly any results.

  • eagle338
    eagle338 Nov 10, 2010

    Thats not necessary. I will just upload it to mediafire and get you the link.

  • eagle338
    eagle338 Nov 10, 2010
  • eagle338
    eagle338 Nov 10, 2010

    Oh, so you haven't checked all the caps? Yes that seems to be the problem. You have got the service manual now, there's a detailed schematic in it. Check the voltages and see if any of them are missing. As for the diode, you can just check if its shorted.

  • eagle338
    eagle338 Nov 10, 2010

    Ok. I do not advice replacing the diode with an inductor though. As you may know the diode will not allow the current to flow in reverse bias mode, where as an inductor has no such thing. Its just a temporary solution, I would say.

  • eagle338
    eagle338 Nov 10, 2010

    You are welcome. If you do get stuck somewhere. Let me know and I will see you through it.

  • eagle338
    eagle338 Nov 11, 2010

    On which board and which component?

  • eagle338
    eagle338 Nov 11, 2010

    Oh. Thats the one going to the inverter. I forgot to ask you do you have sound?

  • eagle338
    eagle338 Nov 11, 2010

    Well thats a tricky situation. What do you wanna do, try and replace the power board?

  • eagle338
    eagle338 Nov 11, 2010

    Well lets continue the diagnosis. Its a tricky situation. I do not want to take a chance and tell you to replace the wrong board. Reading page 70 I have seen that pin 6 has not function. Also by gray screen do you mean that the backlight is lit?

  • eagle338
    eagle338 Nov 11, 2010

    Oj. Just seen it and it confirms that its a power board issue. So I think you can go ahead and replace the power board.

  • eagle338
    eagle338 Nov 11, 2010

    Sure thing.

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